Do you want to move a XenForo forum from a subdomain (like say forum.yourdomain.com) to the root domain (yourdomain.com)? The process is fairly simple and easy to follow. Here is a complete step by step guide.
XenForo admin area isn’t inside a directory but is accessible via the admin.php file. So one can’t add htaccess based password protection to a directory
CPanel and Plesk provide an easy to use front end option to create databases, create users and assign correct permissions to be able to use in XenForo.